The vanishing monarch butterfly

It's one of the insect world's most fantastic feats - the mass migration of monarch butterflies to their winter home in Mexico.

It's one of the insect world's most fantastic feats - the mass migration of monarch butterflies to their winter home in Mexico.

Robert F. Kennedy Jr.

Save the monarch butterflies!

Nearly every autumn, I head to the hills to band and release hawks, eagles and other powerful raptors as they ride the mountains' updraft on their southern migration. While there, I always used to marvel at another autumnal migrant, tiny but no less magnificent — monarch butterflies, flapping earnestly on their delicate wings, dappling the ridge top orange and black.

Although they weigh less than a tenth-of-an-ounce, the monarchs' 2,500-mile annual transcontinental journey to Mexico is longer than that of most raptors. They fly north from Mexico across the Midwest and up the eastern seaboard, to Canada — and back again, all in one summer. The yearly trek requires several generations.

Somehow, the butterflies in the final summer generation decide to embark on this impossible journey crossing mountains, oceans and deserts to reach a place they've never been, a mountainous mecca west of Mexico City where their great grandparents departed months earlier. There they survive the winter, roosting by the millions.

We have little grasp of the kinetics that animate this pilgrimage, but, like me, people everywhere used to thrill at the monarchs' arrival in their yards, parks and neighborhoods. On the ridge each fall we routinely used to see several hundred monarchs a day. Last autumn, for the first time in 30 years, I saw none. I was witness to a crisis. And from what I have heard from friends in the Midwest, you are probably bearing witness too. How many monarch butterflies can you remember seeing this summer?

The annual migration of the monarchs, one of the most inspiring natural phenomena on the planet, may be coming to an end. The population count in Mexico plunged from a billion strong a decade ago to just 33.5 million this year, and an expert declared that the migration is "at serious risk of disappearing." The principal culprit of their decline is a rapacious industrial agriculture system.

Scientists say deforestation in Mexico, drought and climate change may be contributing to the monarchs' peril. But a main cause, they agree, is the soaring use of the powerful weed killer glyphosate, first marketed as Roundup by biotech giant Monsanto. Roundup is wiping out milkweed, the only plant that monarch larvae can eat.

Long one of the most effective weed killers on the market, glyphosate's use skyrocketed since the late 1990s when Monsanto introduced "Roundup Ready" corn and soybeans. Midwestern farmers quickly adopted those genetically engineered herbicide-resistant seeds, which now account for an estimated 72 percent of corn and 94 percent of soybeans.

Farmers can now blanket their fields with the herbicide without harming their crops — but very efficiently killing any milkweed in the way. The result: Glyphosate use has risen tenfold and devastated the monarchs' milkweed habitat.

It's not too late to save the monarchs. But we need to act quickly to make room for the plant they need to survive.

The Natural Resources Defense Council has already filed a petition with the Environmental Protection Agency to place some common-sense limits on glyphosate use, such as requiring farmers to set up herbicide-free safety zones around the edges of their fields, and banning the use of glyphosate and other weed killers along highways and power-line rights of way, where milkweed could flourish harmlessly. Last week it sued to block another chemical cocktail made of glyphosate and 2,4-D, another herbicide.

State and local highway departments and utilities can act now by stopping the wholesale use of glyphosate immediately with no adverse impacts on safety or maintenance.

Next, we need to get more people to plant milkweed. Homeowners, schoolchildren, landowners and others can all spread milkweed seeds along the monarchs' migratory route, creating a "butterfly highway." The White House has created an interagency Pollinator Health Task Force to develop plans to save bees, butterflies and other at-risk pollinators.

Finally, we need to rethink the industrialization of our agriculture system, which routinely yields unintended consequences. Other herbicide-resistant transgenic crops are in the pipeline that will further decimate milkweed unless we adopt appropriate safeguards now. In managing our food supply, the top priority should be to protect consumers and the environment, not the profits of giant agri-businesses.

The eagles and falcons that soar south every autumn once faced extinction from the pesticide DDT. An earlier generation of conservationists, scientists and public officials saved them. This generation can save the monarch migration. We don't want to be the last to witness the marvel of the monarch's journey.

Robert F. Kennedy Jr., a licensed master falconer, is president of Waterkeeper Alliance and a senior attorney with the Natural Resources Defense Council.

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